CERA study of 811 oil fields show that depletion rates will be 4.5% worldwide. Schlumberger's estimate is higher at 8%. CERA is on the optimistic side when it sees two Irans making up for one Iran lost. CERA estimates by 2017 33 million barrels a day will be lost from depletion. still it believes production would go up by 59 million barrels a day to 112 barrels a day. How can it say 59 its anoptimistic estimate of new stuff that will come out of the Caspian, Africa, Russia and other places in Asia and upto now unknown places. The reason its hard to estimate depletion is that OPEC and Russia are not sharing the data. CERA's estimate includes also stuff that comes from biofuels and natural gas liquids as half of that 59. As that 59 is 6 times today's Saudi output the estimates are coming under criticism and not widely accepted. IEA estimates demand will go up by 2.3% to 87.8 million barrels a day. But things may change as fuel efficiency becomes a big factor in reducing consumption and as millions of Asians join the world economy from rural areas the impact of more cars may not be as severe with cars that give 60 or so miles per gallon like the Tata Nano and the competitors it creates. And in the west the USA may not be so wasteful as it has been to make up for the increases in Asia of new motorists and industrial uses of energy. Meantime the gains from exploration at today's prices may provide additional output though not by what CERA's overestimate. ...